SeasonScore
Koh Samui, Thailand
Photo: Ssuri · CC BY-SA 3.0

Thailand

Koh Samui in May

☀️ Dry season

Hot, humid and often rainy.

🎒 Pack: light, breathable clothes & sunscreen · compact umbrella or rain jacket · quick-dry fabrics

Best months: Feb (8.3), Jan (8.2), Mar (8.2)

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Why May scores 8.0What goes into the score

How it works
🌡️ 33° / 26°C🌧️ 132 mm💧 dew pt 25°🍃 PM2.5 4
  • Weather comfort6.4
    • !Hot (33°C highs / 26°C lows)
    • !Very humid/sticky (dew point 25.1°C)
    • !Wet: ~132 mm rain, ~3 heavy-rain days
  • Air quality10.0
    • ✓Good (within WHO guideline) (PM2.5 ~4 µg/m³)
  • Seasonal hazards10.0
    • ·No notable seasonal hazards
  • Safety baseline8.0
    • ·Normal precautions
Compare monthsPut May side by side with another month
MayFeb
Score8.0 Very good8.3 Very good
Season☀️ Dry season☀️ Dry season
High / low33° / 26°29° / 25°
Rain132 mm64 mm
Humiditydew pt 25°dew pt 23°
PM2.54 µg/m³21 µg/m³

Typical-month data: NASA POWER (MERRA-2 reanalysis) 2015–2024 (modelled, not a forecast). Temperatures: Ko Samui weather-station normals. Rainfall: Ko Samui weather-station normals (national met service).

Holidays & crowdsMay 2027

Long weekend

There's at least one long weekend. Domestic travel picks up and popular spots get busier over those days.

  • National Labor Day 1–4 May · 4 days off in a row

Other public holidays: Visakha Bucha (20 May)

National holidays only; regional holidays and school breaks aren't included. Source: holidays (open-source public-holiday calendar).

Explore Koh SamuiEvents, sights, food & souvenirs

Check event dates locally

Thailand's second-largest island, in the Gulf of Thailand, visited for beaches, resorts, temples and boat trips to the Ang Thong marine park.

Events in May
Rocket Festival (Bun Bang Fai)Across Thailand

Villages launch homemade rockets to summon rain for the rice season.

Coming up later

Loy KrathongDate variesThai lunar calendar, usually November

People float candlelit offerings on the water.

Why go: It falls in the rainy season on Samui.

Where: Beaches and temples

SongkranEvery year13-15 April every year

Thai New Year, celebrated with water fights in the streets.

Why go: Expect to get soaked; keep phones in waterproof bags.

Where: Island-wide, especially Chaweng